JPS5920595Y2 - solar heat collector - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a vacuum tube type solar heat collector, and in particular, the invention relates to a vacuum tube type solar heat collector, in particular, a structure in which both ends of a bellows that absorbs thermal displacement of a heat collection pipe inserted into a vacuum transparent outer tube and other members are connected to each other. This allows welding with brazing material to be easily and reliably performed using a high-temperature atmosphere furnace, and also prevents other members from damaging the bellows during use of the solar collector.

A vacuum tube type solar heat collector houses a heat collecting pipe 3 having a heat absorbing member 2 such as a metal plate formed with a selective absorption film in a transparent outer tube 1 that can transmit sunlight, and the heat collecting pipe 3 is connected to an end plate. 4, both ends of the transparent outer tube 1 are sealed, and the inside of the tube is evacuated.

Among such vacuum tube type solar heat collectors, those having a structure in which the heat collecting pipe 3 is drawn out from both ends of the transparent outer tube have at least one of the holding parts of the heat collecting pipe 3 at both ends. is joined to the end plate 4 via the bellows 5, thereby,
Even if the heat absorbing member 2 and the heat collecting pipe 3 are exposed to conditions with a temperature difference exceeding 100°C, thermal displacement of the heat collecting pipe is prevented from destroying the airtight joint.

However, while the bellows 5 that absorbs such thermal displacement is made of a corrosion-resistant metal such as stainless steel, it also needs to be formed from a thin metal plate to prevent fatigue failure even with frequent repeated displacement. Therefore, if strong welding flame hits when welding airtightly with other parts, the bellows 5, end plate 4, and heat collecting pipe 3 may be damaged due to thermal displacement of the heat collecting pipe 3. Intermittent contact of the transparent outer tube is likely to cause perforation in the contact area or breakage of the vacuum inside the transparent outer tube.

The present invention, which was created in view of these points, prevents damage to the bellows during the manufacture of such vacuum tube type solar collectors, and also prevents contact between the bellows and other components under all conditions during use. The purpose is to prevent damage to the bellows due to
This will be explained below according to the drawings.

FIG. 2 is an enlarged sectional view of part II in FIG. 1 showing an embodiment of the present invention, and the transparent outer tube 1, heat collecting pipe 3, end plate 4, and bellows 5 have the same drawing numbers as in FIG. 1. This is an indication.

Further, 6 is a connecting pipe used to join the bellows 5 and the heat collecting pipe 3, and has a connecting exhaust port 8 on the side surface of the bleed pipe 7 for discharging the gas inside the pipe.

The end plate 4 attached to the end of the transparent outer tube is almost entirely curved inward of the outer tube, and a through hole 9 is bored in the center with the peripheral edge widened inward of the outer tube. It is.

The bellows 5 disposed on the outer periphery of the heat collecting pipe 3 has a reduced diameter end 5a having a smaller outer diameter than the other part through a stepped part 10 at one end, and an enlarged end that spreads out in a funnel shape at the other end. The diameter-reduced end 5a is press-fitted into the peripheral edge 4a of the through hole of the end plate 4.

Like the bellows 5, the connecting pipe 6 disposed on the outer periphery of the heat collecting pipe 3 has a reduced diameter end 6a having a reduced outer diameter than the other part through a step 11 at one end, and a heat collecting pipe at the other end. The bellows 5 has a constricted end 6b that joins with the outer circumferential wall of the bellows 5, and the reduced diameter end 6a is press-fitted inside the expanded end 5b of the bellows 5.

Then, while using the stepped portions 10 and 11 of the bellows 5 and the connecting pipe 6 for positioning, both ends 5a of the bellows 5,
5b is brought into pressure contact with the end plate 4 and the connecting pipe 6, between the through-hole peripheral part 4a of the end plate 4 and the stepped part 10 of the bellows 5, and between the expanded end part 5a of the bellows 5 and the stepped part of the connecting pipe 6. 11 and 12 and 11 are arranged in the same direction (to the right in the figure) as solder material storage grooves 12 and 13.

In the solar heat collector of this embodiment having such a structure, in the process of joining the end plate 4 and the bellows 5, and the joining process of the bellows 5 and the connecting pipe 6, the respective brazing material storage grooves are inserted after each member is assembled. 12. Stand with 13 facing upwards,
After placing the solder material 14 in this groove, if it is placed vertically in a high-temperature atmosphere furnace, the enlarged end 5b of the bellows 5 will be funnel-shaped and the end plate 4 will be curved inward into the outer tube. , a brazing material storage groove 12 at each joint to which the molten brazing material 14 is pressed.
It goes around this groove 12.13 without flowing out from 13.

Therefore, the bellows 5 can be hermetically joined to the end plate 4 and the connecting pipe 6 at the same time without being exposed to the welding flame, making the welding work easier and more reliable than when brazing is performed under the welding flame. At the same time, damage to the bellows during manufacturing the solar heat collector can be significantly reduced.

In addition, since the connecting pipe 6 is thicker than the bellows 5, after the bellows 5 is joined, the constricted end 6b can be brazed to the heat collecting pipe 3 under a welding flame. be.

Also, the stepped portion 10 formed on the bellows 5 and the connecting pipe 6.
11 functions as positioning when forming the brazing material storage grooves 12 and 13, so on the left side of the figure, a sufficient gap is formed between the outer surface of the bent portion 5C of the bellows 5 and the end plate 4, On the right side of the figure, a sufficient gap d can be secured between the inner surface of the bent portion 5C of the bellows 5 and the reduced diameter end 6a of the connecting pipe 6. 6, so that a suitable distance from the outer peripheral surface of the heat collecting pipe 3 is maintained.

As a result, in the solar heat collector of this embodiment, the bent portion 5C of the bellows 5 comes into contact with other members under all conditions during use, including mechanical overdisplacement during installation of the heat collector. It is possible to obtain a solar heat collector with excellent durability by compensating for the weak mechanical strength of the bellows, which uses a thin metal plate material.

Furthermore, since the end plate 4 is curved toward the inside of the outer tube, the stress of the vacuum pressure applied to the end plate 4 is dispersed when the inside of the transparent outer tube 1 is evacuated and during use of the heat collector. Thus, the joint between the reduced diameter end 5a of the bellows 5 and the peripheral edge 4b of the through hole of the end plate 4 can be prevented from peeling off.

As described above, the present invention includes a transparent outer tube that maintains a vacuum inside the tube, and a flap that is attached to the end of the outer tube. An end plate having a through hole in the center that expands toward the outside, a heat collecting pipe inserted into the transparent outer tube through the through hole of the end plate, and a heat collecting pipe arranged around the outer periphery of the heat collecting pipe with a stepped portion at one end. A bellows has a reduced diameter end with a reduced outer diameter, and an expanded end with a funnel-shaped expansion at the other end, and the reduced diameter end is press-fitted into the peripheral edge of a through hole of an end plate. Like the bellows, it is arranged on the outer periphery of the heat collecting pipe, and has a reduced diameter end whose outer diameter is reduced through a step at one end, and a constricted end that joins the outer peripheral wall of the heat collecting pipe at the other end. and a connecting tube with a reduced diameter end press-fitted inside the expanded end of the bellows, and between the peripheral edge of the through hole of the end plate and the step of the bellows, and between the expanded end of the bellows and the connecting tube. This structure has a solder material storage groove formed in the same direction between the step part and the step part, and has the following effects.

■ While the reduced diameter end and expanded end of both ends of the bellows are brought into pressure contact with the end plate and the connecting pipe, the peripheral edge of the central through-hole of the end plate curved inward of the transparent outer tube and the step of the bellows. Since we have formed a brazing material storage groove in the same direction between the bellows and the stepped part of the connecting pipe, and between the funnel-shaped expanded end and the step of the connecting pipe, welding of the bellows and other parts can be performed using a high-temperature atmosphere furnace. At the same time, the welding process can be carried out without failure, making the welding work simple and reliable, and there is no need to worry about the bellows being exposed to welding flame during manufacture and being damaged.

■ The joints at both ends of the bellows can be positioned by the bellows and the step part of the connecting pipe so that other parts are pressed against the bent part at the center of the bellows by a predetermined distance, and the bellows can be properly connected to the outer periphery of the heat collecting pipe via the connecting pipe. Since the bellows can be arranged at a certain distance from each other, the bent part of the bellows can be prevented from coming into contact with or rubbing against other parts under all conditions during the use of the heat collector, and the mechanical strength of the bellows can be weakened. This makes it possible to obtain a solar heat collector with excellent durability.

■ Since the end plate is curved inward of the transparent outer tube, by creating a vacuum inside the transparent outer tube, the stress of the vacuum pressure applied to the end plate is dispersed, and the joint between the bellows and the end plate is can be prevented from peeling off.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an example of a vacuum tube type solar heat collector according to the present invention, and FIG. 2 is an enlarged sectional view of section II of FIG. 1. DESCRIPTION OF SYMBOLS 1... Transparent outer tube, 3... Heat collection pipe, 4... End plate, 4a... Through-hole periphery, 5... Bellows, 5a.
... Reduced diameter end, 5b... Expanded end, 5C... Bent part, 6... Connecting pipe, 6a... Reduced diameter end, 6b... Curved end, 9...・Through hole, 10, 11... Step part, 12
．． 13...Brazing material storage groove, 14...Brazing material.

Claims (1)

[Scope of utility model registration request] A transparent outer tube that maintains a vacuum inside the tube, and a through hole that is attached to the end of the outer tube, the entire length of the tube is curved inward, and the periphery is widened inward. An end plate in the center, a heat collecting pipe inserted into the transparent outer tube through a through hole in the end plate, and a condensing pipe arranged around the outer periphery of the heat collecting pipe and having a stepped part at one end to reduce the outer diameter. A bellows that has a diameter end and an enlarged funnel-shaped end at the other end, the reduced diameter end being press-fitted into the periphery of the through hole of the end plate, and the outer periphery of the heat collecting pipe like this bellows. and has a reduced diameter end portion having a reduced outer diameter via a stepped portion at one end,
The other end has a constricted end that joins with the outer peripheral wall of the heat collecting pipe,
A connecting tube with a reduced diameter end press-fitted inside the expanded end of the bellows, and a space between the peripheral edge of the through hole of the end plate and the stepped portion of the bellows, and between the expanded end of the bellows and the stepped portion of the connecting tube. A solar heat collector with a brazing material storage groove in the same direction between the